Folding bicycles have been known for many years. These bicycles conventionally comprise a hinge system located in the down tube of the frame which allows laterally folding the back portion of the bicycle over the front portion.
In different pedal-assist bicycle models, the battery is located precisely in the down tube of the frame, such as for example in the frame described in Utility Model ES-ES1072110-U, so it is impossible to provide the down tube with an articulation or hinge. In order to provide pedal-assist bicycles in which the battery is arranged in the diagonal frame of the frame, folding systems have been conceived such as the one described for example in patent application WO03022671A1, which allows laterally folding the back portion of the bicycle over its front portion based on an articulation provided in the attachment of the down tube with the seat tube. However, the location of this articulation is at a point where many loads coincide when the bicycle is in use, so this system is complicated and susceptible to breaks.